Work out a watering routine for my actual conditions

The label says "water regularly" and you have killed three plants finding out what that means.

Build me a watering approach for the specific plants and conditions below.

1. Group my plants by watering need rather than listing them individually, so I have three or four groups instead of a schedule per plant.
2. For each group, give me a **test** rather than an interval: how deep to push a finger, what the pot should weigh, what the leaves do first. Intervals fail when the weather changes.
3. State how the conditions I describe shift things: pot material, pot size, light level, heating, draughts, humidity, and whether it is summer or winter.
4. Give the early warning signs of overwatering and of underwatering for these specific plants, since they look similar and the wrong response kills faster.
5. Tell me what to do about holidays, by group.

Then name the single plant in my list most likely to die from my described habits, and say why.

Plants:
Where they are and what light they get:
Pots and compost:
How I currently water, honestly:

Routine care. Watering tests, repotting calls, pruning timing, compost mixes, and taking cuttings that root.